Roof mounting support for photovoltaic modules on uneven roofs

ABSTRACT

A mounting support for mounting at least one photovoltaic module having a glass pane on a top side of an, in particular, uneven roof panel includes an elongated strip which can be rolled up and/or unrolled in a roll-up/unroll direction. At least two attachment means for the photovoltaic module are disposed on the strip with a modular dimension. The bottom side of the support is provided in the region of the attachment means with a protruding padding to compensate for uneven roof areas. The top side of the attachment means is provided with a supporting location or surface for edges of the photovoltaic module. The mounting support can be packaged as a roll and attached in a simple and effective manner on uneven and rough roof shingles.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the priority of German Patent Application, Serial No. 10 2009 037 720.4, filed Aug. 17, 2009, pursuant to 35 U.S.C. 119(a)-(d), the content of which is incorporated herein by reference in its entirety as if fully set forth herein.

BACKGROUND OF THE INVENTION

The present invention relates to a mounting support for mounting a photovoltaic module having a glass pane on the top side of an, in particular, uneven roof panel.

The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.

Presently, two approaches are used for installing a solar collector system on a flat roof or an inclined roof, as described with reference to FIGS. 1 and 2. As illustrated in FIG. 1, concrete blocks 1 are placed on the roof and a corresponding support structure 3, on which conventional photovoltaic modules made of glass are mounted, is connected with the concrete blocks 1. Disadvantageously, this structure is heavy and must be taken into consideration in the static design. Moreover, large quantities of material are required. Conversely, this approach has advantageously a high efficiency, because photovoltaic modules with one or two glass panes can be installed at a favorable angle.

According to the second approach, a mounting foil 7 is glued onto the flat roof and is subsequently joined with a module foil 9. This embodiment has a small roof load and low material costs; however, the efficiency of module foils is low. Installation is simple and advantageous, because the foil 7, 9 needs only to be installed in a single roll-up/unrolling direction 11 and joined with the roof panel by gluing or welding.

For example, EP-A-08 018 443 discloses a support having the shape of an elongated strip. The bottom side of the support has a substantially planar structure and can therefore be readily joined with the roof panel. The top side of the support is interrupted by openings which extend transversely to a roll-up/unrolling direction from one edge to the other, thereby forming segments delimited by the openings. In one part of the segments, a respective attachment means for the photovoltaic modules is integrated, wherein the photovoltaic modules are arranged with respect to one another in the roll-up/unrolling direction in a predetermined grid pattern. The support is only suitable for roofs with a flat, smooth roof panel made of, for example, foil, copper sheets or galvanized sheets, because the support is glued or welded to the roof panel. In addition, the support must extend across a large area, because the support must be able to absorb the load of the photovoltaic modules, as well as snow and wind forces.

It would be desirable to address this problem and to obviate other prior art shortcomings by providing a support for PV modules which is used only to orient and adjust the individual PV modules, which is capable of absorbing forces, provided that the roof construction can sustain the forces. It would furthermore be desirable to provide a support that can be rolled up and unrolled, which can be readily transported and handled due to its low weight, thereby allowing a precise orientation of the PV modules with respect to one another. The support should also be usable on uneven and rough surfaces. This additional characteristic property is advantageous in particular with roofs having roof panels made of shingles which are uneven at their overlaps, for example have a step or a shoulder, making gluing or welding impossible. This applies particularly to roofs widely used in the USA which are made of sand-coated roofing felt shingles, but also to domestic roofs covered with wooden shingles.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a mounting support for mounting at least one photovoltaic module having a glass pane on a top side of a roof panel, includes an elongated strip constructed to be rolled up or unrolled, or both, in a roll-up/unroll direction, at least two attachment means disposed on the strip a having a modular dimension for attachment of the at least one photovoltaic module, a supporting location for an edge of the photovoltaic module disposed on a top side of the attachment means, and a padding protruding from a bottom side of the support disposed in a region of the attachment means to compensate for uneven areas of the roof panel.

According to another aspect of the invention, a method for mounting a photovoltaic system having a plurality of photovoltaic modules on an uneven roof panel applied on a wooden structure with a mounting support with the mounting support described above includes the steps of attaching a first part of the attachment means with screws to the wooden structure, placing an edge of a first photovoltaic module on the supporting surfaces of the first part of the attachment means, placing a second part of the attachment means on the roof panel such that the edge of the first photovoltaic module is arranged on the supporting location or a supporting surface of the second part of the attachment means, and attaching the second part of the attachment means with screws to the wooden structure. The padding seals damage to the roof panel caused by the screw-attachment to the wooden structure.

According to yet another aspect of the invention, a method for mounting a photovoltaic system having a plurality of photovoltaic modules on an uneven roof panel applied on a wooden structure with the mounting support described above includes the steps of attaching a first part of the attachment means with screws to the wooden structure, placing a second part of the attachment means on the roof panel in such a manner that the at least one strip is under tension, attaching the second part of the attachment means with screws to the wooden structure, and placing and clamping the photovoltaic modules on the supporting location or supporting surface of the attachment means. The padding hereby also seals damage to the roof panel caused by the screw-attachment to the wooden structure.

In the simplest embodiment, the aforementioned support includes a strip having along its length or at its ends respective attachment means, which are spaced by a distance determined by the modular pattern or the modular dimension. The spacing corresponds essentially to the height of the PV modules to be mounted plus one-time the gap between adjacent modules. Depending on the employed module, a different modular dimension can be selected. It is important that the modular dimension is always adapted to the dimensions of the module. In other words, when the PV module is mounted on the edge, the aforementioned width defines the modular dimension. A potentially different (i.e., shorter) modular dimension may be selected when the module is attached on the bottom side of the PV module. The padding protrudes a certain height from the bottom side of the support, wherein the height is selected so that the thickness is at least twice the thickness of conventional roof shingles, in addition to an upsetting distance which is required for pressing the padding form-fittingly and moisture-tight onto the uneven, sand-coated roof shingle. In the subsequently described installation of the support, the padding is, depending on its relative position to the shingle, pressed against the shingle or into the step or gap formed by an overlap. The top side of the support facing the sky is provided with one or more supporting surfaces, which serve as placement or supporting surface for the PV module to be installed. With the invention, photovoltaic modules based on glass technology can advantageously be used without the need for a heavy substructure.

According to a modified embodiment of this basic pattern, a plurality of attachment means is attached on a strip having a length exceeding one meter, and the modular dimension forms a spacing of between 60 cm and 125 cm between the attachment means. The term “exceeding one meter” is intended to indicate that at least two PV modules can be attached on top of one another on the same strip. In practice, the strip may have a length of several meters, e.g., 20 to 50 meters, and may be cut to the desired length at the installation site. For example, several strips having a length of 7 meters, which then extend parallel to one another, can be cut for a roof having a length between roof ridge and gutter of 8 meters, with the plurality of attachment means forming respective rectangles. Likewise, in a modified embodiment having this arrangement of parallel strips, more than two mutually parallel strips may be provided which form a grid pattern where the attachment means are located at the nodes of rectangles arranged in a checkerboard pattern.

In particular, with this grid shape of the support, transverse rails are advantageously provided which connect the opposing attachment means with each other. The strips themselves should, compared to the dimensions of the attachment means, form a relatively wide longitudinal rail connecting pairs of respective attachment means with each other. This width is required so that the position of the attachment means is maintained during the screw-down operation without rotating the attachment means. However, the strip should not protrude over the width of the attachment means. If the attachment means forms, in a top view, a rectangle with edges having lengths in a range between 5 cm and 12 cm, then a width of the strips (referred above also as longitudinal rail) should be between 8 cm 12 cm and the width of the transverse rails between 1 cm and 3 cm. A different, i.e. wider, width of the transverse rail may be selected if due to the employed material a rotation lock of the attachment means during screw-down can only be attained by stiffening the grid in a second direction. A small thickness of the strips and of the transverse rails should be selected, so that they are flexible and can be easily rolled up or unrolled. A thickness between 0.5 mm to 2 mm is sufficient because the thickness is required only for adjusting the attachment means. This takes into consideration that the support should be easy and comfortable to handle, facilitating a correct orientation and positioning of the attachment means, which are only subsequently joined with the roof panel and the structure underneath.

If the grid it is not too wide, i.e., for example, the width is adapted for a single PV module up to a maximum of three PV modules (corresponding to two to four attachment means positioned side by side), then the strips, the transverse rails and the attachment means may form an integral injection-molded plastic part. Assuming a module width of 120 cm and a position of each of the attachment means of 30 cm from the edge of the narrow side of the module for a spacing between modules of 5 cm, then the grid width will be about 70 cm for a single PV module installed width-wise (distance 60 cm plus twice half the width of the attachment means itself which has a width of 10 cm), and of 195 cm for two PV modules installed side-by-side, and additionally 125 cm for each additional adjacently installed PV module. With a 50 m long rolled-up grid for a single module width, adjustment and attachment supports for 77 PV modules can be provided with a height of the PV module of 60 cm. With a 195 cm wide grid for two adjacent PV modules already for 150 for PV modules, with a 220 cm wide grid for three adjacent PV modules for 231 PV modules, etc. Advantageously, the support, in particular when implemented as an injection molded part, is provided with means for routing an electric cable. This may be accomplished either with clamps or clips, in which the conventional wiring cables for the PV modules are snapped in, or the electrical cables themselves are connected with the injection molded part, for example integrated therein, so that only their terminals are routed to the outside, or the cables are permanently mechanically attached, for example glued or welded, to the top side of the strips and rails.

PV modules with metallic frames may not require attachment means with a rubber support. However, for grounding, the attachment means or at least parts of the strip should be made of metal.

The padding on the bottom side of the mounting support should have at least one of the following characteristic properties: it is made of an elastic material, it is made of a hydrophobic material, it has a structure exerting a spring force, it has a chamber that is open towards the bottom and filled with a material capable of flowing under pressure, and/or it is made of a sealing mass, for example cellular rubber impregnated with bitumen. Because the padding comes into contact with rainwater, the material must be insoluble in water. It may be, for example, a swelling material which swells when exposed to moisture. In this way, the sealing action of the padding increases over time. A structure exerting a spring force provides, for example, that the padding is made of an elastic material and provided with cavities. During compression, the cavities have the tendency to return to their original shape and therefore provide a sealing effect. Advantageously, the cavities or chambers are provided with a lower opening oriented towards the roof panel. A material which becomes liquid under pressure and is squeezed out of the opening may be introduced into this chamber. This is particularly advantageous when a gap is encountered accidentally. In this case, the sealing compound contained in the pockets or pores enters the gap in a liquid state.

For attaining a defined height of the PV module on the attachment means, the top side of the attachment means is provided with one or two supporting locations for the edge of the PV module, for example for the two edges of adjacent PV modules. To prevent point loads on the glass of the installed PV module, the supporting locations may advantageously be configured as supporting surfaces which are separated from each other by a separation wall operating as a stop. The separation wall prevents the two edges of adjacent PV modules, which are clamped using the same attachment means, from striking each other. The separation wall may also be formed in two parts, with one part for one photovoltaic module and another part for the other adjacent photovoltaic module. The gap between the separation parts, which can also be viewed as forming separate stops, should be as large as possible to reduce material use and weight. To facilitate the attachment means to be screwed to the wooden roof structure, the material is thinned, preferably in the central region of the attachment means, and can be easily penetrated by a self-threading screw.

The support for PV modules having a metal frame can be completely prepared in the factory, because the clamping part is narrower than the module spacing, because the module frames can also withstand point loads. An opening for penetration of the screw is also advantageous, in particular if the opening is sized so that the tip of the screw can be easily screwed in and securely held in place. With this approach, a clamping part which after installation exerts on the photovoltaic module a force directed towards the supporting surface should be added to the attachment part before. The clamping part should be somewhat narrower than the spacing between two adjacent PV modules. In this way, the clamping part can already be installed in the factory together with the screw inserted into the opening. When the PV module is placed onto the supporting surfaces of the attachment means, the clamping parts are initially rotated in a longitudinal direction parallel to the module edge and are then rotated perpendicular to the module edge after the placement of the PV module, before the screw is screwed into the wooden structure, in particular the wooden covering boards of a shingled roof, and tightened, whereby the PV module is clamped down.

According to a variant of the aforedescribed solution using a screw, several screws may be used, wherein the attachment means is provided in the central region with a blind hole, which alone or an inserted sleeve have an interior thread, and wherein in addition to the blind hole two spaced-apart thinned regions or recesses are provided in the material which are arranged mirror-symmetrically in relation to the blind hole. With this variant, the force required to clamp the PV module is advantageously not transferred to the roof panel and its substructure, but remains entirely inside the attachment means and is absorbed by the machine screw which tightens the clamping part in the direction towards the attachment means.

Regarding the method for installing the photovoltaic module, the object is solved according to a first embodiment of the invention in that in a first method step a first part of the attachment means is screwed down on the wooden structure, that in a second method step one edge of the photovoltaic module is placed on the supporting surfaces of the first part of the attachment means, that in a third method step a second part of the attachment means is placed on the roof panel such that the edge of the previously placed photovoltaic module facing the one edge is placed on the supporting surfaces of the second part of the attachment means, and that in a fourth method step the second part of the attachment means is screwed down on the wooden structure, wherein the padding seals any damage to the roof panel caused when the screws are screwed into the wooden structure. With this installation method, the strips or longitudinal rails of the mounting support can be dimensioned to be somewhat longer than required for the exact spacing. The attachment means is then no longer used to set the spacing at the same time: because one edge of the PV module already makes contact with the stop of one attachment means, whereas the stop of the other attachment means only needs to be moved to the other edge of the module, where it is fixed in place.

The second embodiment of the invention is different in that the object is solved in that in a first method step a first part of the attachment means is screwed down to the wooden structure, that in a second method step a second part of the attachment means is placed on the roof panel in such a manner that the strip(s) and optionally the transverse rails is/are under tension, that in a third method step the second part of the attachment means is screwed down to the wooden structure, and that in a fourth method step the photovoltaic modules are placed on the supporting surfaces of the attachment means where they are clamped, wherein the padding seals any damage to the roof panel caused when the screws are screwed into the wooden structure. With this installation method, the complete substructure for the PV modules can be finished first, before subsequently all PV modules are placed sequentially or, when using several installers, concurrently onto the support in a single operation and fixed with the associated clamping part.

As described above, with both approaches, the clamping means associated with the attachment means for clamping and affixing the photovoltaic modules can be installed at the same time the attachment means are screwed down on the wooden structure. In addition, with both variants, the grid can advantageously already be cut to size according to the available roof shape and roof size before installation, possibly already at the manufacturing site of the mounting support, before the grid is installed, thereby forestalling any inconvenience during the actual installation.

BRIEF DESCRIPTION OF THE DRAWING

Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which:

FIG. 1 a conventional installation method for photovoltaic modules on a flat roof;

FIG. 2 conventional installation method for a photovoltaic foil on a flat roof;

FIG. 3 a cross-section through a detail of a mounting support according to the invention with two installed attachment means;

FIG. 3 a a detailed view of FIG. 3 with a single-screw embodiment;

FIG. 3 b a detailed view of FIG. 3 with a three-screw embodiment;

FIG. 4 a basic arrangement of the mounting support according to the invention;

FIG. 5 a modification of the basic arrangement enlarged to an elongated strip;

FIG. 6 a modification of the basic arrangement enlarged to a rectangle;

FIG. 7 a modification of the basic arrangement enlarged to the shape of a rope ladder;

FIG. 8 a modification of the basic arrangement enlarged to a grid.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Throughout all the figures, same or corresponding elements may generally be indicated by same reference numerals. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figures are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.

Turning now to the drawing, and in particular to FIGS. 3, 3 a and 3 b, there is shown with the reference symbol 11 a mounting support for mounting rigid photovoltaic modules 13 on an uneven roof panel. The roof panel is composed of a plurality of shingles 15 which are nailed in overlapping relationship onto a wooden substructure 17, typically with roofing nails (not shown). The shingles 15 may be made of sand-coated roofing felt, wood, or other suitable materials. Due to the overlap, a step 19 is formed in the overlap region, which for an installation of the shingles 15 with an offset is maximally twice the shingle thickness.

The photovoltaic modules 13 are to be installed on this type of roof panel. To this end, the mounting support 11 is composed of a strip 21 having attachment means 23 arranged in regular intervals, the so-called modular dimension. Each attachment means 23 has on its top side two supporting surfaces 25, which each support an edge of adjacent PV modules 13. The two supporting surfaces 25 are separated from each other by a separation wall 27 which prevents adjacent modules 13 from striking each other and also operates as a stop during installation of the PV modules 13. The attachment means 23 has on its bottom side a padding 29 made of an elastic material, operating as a seal when compressed. In the illustrated exemplary embodiment, the padding 29 extends across the entire underside of the attachment means 23. It would also be sufficient to use a round or rectangular padding 29 with a diameter or edge length between 5 mm and 20 mm, as described below when discussing its functionality.

Each of two attachment means 23 are connected with one another by way of the longitudinal rail or strip 21. To illustrate the two variants shown in FIGS. 3 a and 3 b, FIG. 3 shows on the right side a single-screw variant and on the left side the three-screw variant. It should be noted that in reality the support is always equipped with only a single type of attachment means 23. In the illustrated embodiment, the strip 21 and the attachment means 23 are manufactured as a single part, for example, by an injection molding process.

The variant illustrated on the light side in FIG. 3 a includes a bore 31 located in the central region of the attachment means 23. The bore 31 extends perpendicular to the supporting surfaces 25 and is preferably implemented so as to terminate before the padding 29 or to slightly penetrate into the padding. A screw 33 is inserted through the bore 31, and the thread of the screw 33 is screwed into the wooden structure 17 located underneath the shingles 15. A clamping part 35, which has at its bottom side a rubber part 37 to prevent sliding and scratching of the PV modules 13, is provided as an accessory to the attachment means 23. A protective foil (not shown) similar to the rubber part 37 can be applied on the supporting surfaces 25 of the attachment means 23 before installation of the PV module 13.

The diameter of the bore 31 may be larger than the outside diameter of the screw 33, allowing the screw 33 to move freely inside the bore 31. To prepare the mounting support 11 for installation ahead of time, the diameter of the bore 31 should be slightly smaller than the diameter of the exterior thread of the screw 33. In this case, the clamping part 35 can already be positioned during manufacture of the support 11 and can be rolled up together with the mounting support 11, held in place by the screw 33.

As seen clearly in FIG. 3 a, the padding 29 is compressed after the clamping part is pressed against the PV module 13 and protects the region where the screw 33 penetrates the shingles 15 from incursion of moisture.

The complementing FIG. 3 b shows the three-screw variant, where the central bore 31 is replaced with a blind hole 38, with the bottom of the blind hole 38 terminating a safe distance from the underside of the attachment means 23. If the material from which the attachment means 23 is made has a sufficiently high firmness, then the inside of the blind hole 38 can be directly provided with an interior thread. The clamping forces are then directly introduced into the attachment means 23. Conversely, if the attachment means 23 is made of a softer plastic, then a metal sleeve should be anchored therein during manufacture of the attachment means 23, whereby the clamping forces are then transmitted indirectly via the sleeve to the attachment part 23.

FIG. 4 shows a top view onto the basic component of the mounting support 11 in the smallest unit of the strip 21, which forms only a single longitudinal rail, having only one respective attachment means at each of its ends. The PV module 13 is installed on the roof panel by installing two of these basic components next to each other.

FIG. 5 shows the next larger structure, wherein the strip 21 has the length of several meters and includes several attachment means 23. The attachment means 23 are spaced from one another with an identical distance A, thereby forming a modular dimension A. The strip 21 then includes a plurality of longitudinal rails 21 a to 21 e which each connect two corresponding adjacent attachment means 23 with one another.

FIG. 6 shows two adjacent basic components according to FIG. 4, wherein two strips 21 and 21′ are arranged next to each other and the opposing attachment means 23 and 23′ are connected in pairs by way of a transverse rail 39.

A still more complex structure of the mounting support 11 which is prefabricated as a single piece is shown in FIG. 7. The row structure of FIG. 5 is combined with the rectangular structure of FIG. 6, forming a structure similar to a rope ladder. In other words: all attachment means 23 and 23′ located along the strips 21 and 21′ at the same position in the strip 21, 21′ are connected in pairs via a respective transverse rail 39.

The largest possible type of mounting support 11 is obtained when several of the ladder-shaped arrangements of strips 21, 21′ and attachment means 23, 23′ shown in FIG. 7 are combined next to one another into a grid 41, as illustrated in FIG. 8. This Figure also shows the connection scheme of the involved 16 PV modules. The positive terminals of the PV modules are indicated by a plus-sign and the negative terminals with a minus-sign. The cable connections are indicated by continuous thick lines, which need only be connected from one module 13 to the next module 13; a longer connection is sometimes required which can be implemented via external cables with clamps formed on the rails or with electric cables integrated in the rails.

FIG. 4 shows another electric cable 43 which is integrated inside the longitudinal rails 21 and the transverse rail 39. Alternatively, attachment with an adhesive to the bottom or top side of the rail 31:39 may be selected. The ends of the electric cable could either be provided with a first component of a plug connection, or with a contact pad 45 which provides electrical contact to the PV module by way of pressure.

While the invention has been illustrated and described in connection with currently preferred embodiments shown and described in detail, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit and scope of the present invention. The embodiments were chosen and described in order to explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. 

1. A mounting support for mounting at least one photovoltaic module having a glass pane on a top side of a roof panel, comprising: an elongated strip constructed to be rolled up or unrolled, or both, in a roll-up/unroll direction, at least two attachment means disposed on the strip a having a modular dimension for attachment of the at least one photovoltaic module, a supporting location for an edge of the photovoltaic module disposed on a top side of the attachment means, and a padding protruding from a bottom side of the support disposed in a region of the attachment means to compensate for uneven areas of the roof panel.
 2. The mounting support of claim 1, wherein the strip forms a longitudinal rail which has a width greater than a width of the at least two attachment means, with the longitudinal rail connecting with one another two respective attachment means with a spacing defined by the modular dimension.
 3. The mounting support of claim 1, wherein a plurality of attachment means is attached on the strip, with the strip having a length exceeding one meter, and wherein the spacing between the attachment means as defined by the modular dimension is between 60 cm and 125 cm.
 4. The mounting support of claim 1, comprising two mutually parallel strips having at least four attachment means forming a rectangle.
 5. The mounting support of claim 4, further comprising transverse rails, which connect corresponding opposing attachment means with one another.
 6. The mounting support of claim 5, comprising more than two strips producing a grid, wherein the at least four attachment means are disposed at nodes of the rectangles which are arranged in a checkerboard pattern.
 7. The mounting support of claim 1, wherein the strip and the at least two attachment means form an integral injection-molded part.
 8. The mounting support of claim 5, wherein the strip, the at least four attachment means and the transverse rails form an integral injection-molded part.
 9. The mounting support of claim 1, wherein the padding is made of a material selected from the group consisting of an elastic material, a hydrophobic material, and a sealing compound.
 10. The mounting support of claim 1, wherein the padding has a structure exerting a spring force, or comprises a chamber that is open at the bottom side of the support and filled with a material capable of flowing under pressure, or a combination thereof.
 11. The mounting support of claim 1, wherein a top side of the attachment means has two supporting locations or supporting surfaces which are separated from each other by a separation wall operating as a stop.
 12. The mounting support of claim 1, wherein the at least two attachment means comprise a material region of reduced thickness or a bore for lead-through of a screw.
 13. The mounting support of claim 12, wherein the material region of reduced thickness or the bore is located in a central region of the attachment means.
 14. The mounting support of claim 1, wherein the at least two attachment means comprise a blind hole located in a central region, wherein the blind hole or a sleeve inserted in blind hole has an interior thread, further comprising a material region of reduced thickness or bores arranged mirror-symmetrically next to the blind hole in spaced-apart relationship.
 15. The mounting support of claim 4, wherein the attachment means, when viewed from the top, form a rectangle having edges with a length ranging between 5 cm and 12 cm.
 16. The mounting support of claim 1, further comprising in addition to the attachment means a clamping part which, after installation, exerts on the photovoltaic module a force directed towards the supporting location.
 17. The mounting support of claim 5, wherein at least one of the strip, the attachment means or the transverse rail has an integrated electric cable or is provided with clips for routing an electric cable.
 18. A method for mounting a photovoltaic system having a plurality of photovoltaic modules on an uneven roof panel applied on a wooden structure with a mounting support which includes an elongated strip constructed to be rolled up or unrolled, or both, in a roll-up/unroll direction, at least two attachment means disposed on the strip a having a modular dimension for attachment of the at least one photovoltaic module, a supporting location or a supporting surface for an edge of the photovoltaic module disposed on a top side of the attachment means, and a padding protruding from a bottom side of the mounting support disposed in a region of the attachment means to compensate for uneven areas of the roof panel, comprising the steps of: attaching a first part of the attachment means with screws to the wooden structure, placing an edge of a first photovoltaic module on the supporting surfaces of the first part of the attachment means, placing a second part of the attachment means on the roof panel such that the edge of the first photovoltaic module is arranged on the supporting location or a supporting surface of the second part of the attachment means, and attaching the second part of the attachment means with screws to the wooden structure, wherein the padding seals damage to the roof panel caused by the screw-attachment to the wooden structure.
 19. A method for mounting a photovoltaic system having a plurality of photovoltaic modules on an uneven roof panel applied on a wooden structure with a mounting support which includes at least one elongated strip constructed to be rolled up or unrolled, or both, in a roll-up/unroll direction, at least two attachment means disposed on the at least one strip a having a modular dimension for attachment of the at least one photovoltaic module, a supporting location or a supporting surface for an edge of the photovoltaic module disposed on a top side of the attachment means, and a padding protruding from a bottom side of the mounting support disposed in a region of the attachment means to compensate for uneven areas of the roof panel, comprising the steps of: attaching a first part of the attachment means with screws to the wooden structure, placing a second part of the attachment means on the roof panel in such a manner that the at least one strip is under tension, attaching the second part of the attachment means with screws to the wooden structure, and placing and clamping the photovoltaic modules on the supporting location or supporting surface of the attachment means, wherein the padding seals damage to the roof panel caused by the screw-attachment to the wooden structure.
 20. The method of claim 18, wherein a clamping part associated with the attachment means and constructed for clamping and affixing the photovoltaic modules is mounted on the wooden structure at the same time the attachment means are attached with screws.
 21. The method of claim 18, wherein are plurality of strips are arranged in form of a rectangular grid forming a checkerboard pattern, further comprising cutting the rectangular grid to a size corresponding to an existing roof shape and roof size before installation.
 22. The method of claim 19, wherein are plurality of strips are arranged in form of a rectangular grid forming a checkerboard pattern, further comprising cutting the rectangular grid to a size corresponding to an existing roof shape and roof size before installation. 